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Diffstat (limited to 'README')
| -rw-r--r-- | README | 68 |
1 files changed, 34 insertions, 34 deletions
@@ -1,9 +1,9 @@ # SPDX-License-Identifier: GPL-2.0-only -Barebox +barebox ------- -Barebox is a bootloader that follows the tradition of Das U-Boot, while +barebox is a bootloader that follows the tradition of Das U-Boot, while adopting modern design ideas from the Linux kernel. @@ -18,33 +18,34 @@ Features - The environment is not a variable store anymore, but a file store. It has currently some limitations, of course. The environment is not a real - read/write filesystem, it is more like a tar archive, or even more like - an ar archive, because it cannot handle directories. The saveenv command - saves the files under a certain directory (by default /env) in persistent - storage (by default /dev/env0). There is a counterpart called loadenv, too. + read/write filesystem, but more like a tar archive. + The saveenv command saves the files under a certain directory (by default + /env) in persistent storage (by default /dev/env0). There is a counterpart + called loadenv, too. - filesystem support The loader starts up with mounting a ramdisk on /. Then a devfs is mounted on /dev allowing the user (or shell commands) to access devices. Apart from - these two filesystems there is currently one filesystem ported: cramfs. One - can mount it with the usual mount command. + these two filesystems there are a number of different filesystems ported: + ext4, efi, efivarfs, ext4, fat, jffs2, NFS, pstore, squashfs, ubifs, + u-boot variable FS among others. - device/driver model Devices are no longer described by defines in the config file. Instead - there are devices which can be registered in the board .c file or - dynamically allocated. Drivers will match upon the devices automatically. + devices are registered as they are discovered (e.g. through OpenFirmware + device tree traversal or EFI handles) or by board code. + Drivers will match upon the devices automatically. - clocksource support Timekeeping has been simplified by the use of the Linux clocksource API. - Only one function is needed for a new board, no [gs]et_timer[masked]() or - reset_timer[masked]() functions. + no [gs]et_timer[masked]() or reset_timer[masked]() functions. - Kconfig and Kernel build system Only targets which are really needed get recompiled. Parallel builds are no problem anymore. This also removes the need for many many ifdefs in the code. -- simulation target +- ARCH=sandbox simulation target barebox can be compiled to run under Linux. While this is rather useless in real world this is a great debugging and development aid. New features can be easily developed and tested on long train journeys and started @@ -53,7 +54,7 @@ Features devices under barebox to emulate storage devices. - device parameter support - Each device can have a unlimited number of parameters. They can be accessed + Each device can have an unlimited number of parameters. They can be accessed on the command line with <devid>.<param>="...", for example 'eth0.ip=192.168.0.7' or 'echo $eth0.ip' @@ -71,10 +72,10 @@ Features except the ones really needed: moving the cursor and typing characters. -Building Barebox +Building barebox ---------------- -Barebox uses the Linux kernel's build system. It consists of two parts: +barebox uses the Linux kernel's build system. It consists of two parts: the Makefile infrastructure (kbuild), plus a configuration system (kconfig). So building barebox is very similar to building the Linux kernel. @@ -83,7 +84,7 @@ For the examples below, we use the User Mode barebox implementation, which is a port of barebox to the Linux userspace. This makes it possible to test drive the code without having real hardware. So for this test scenario, ARCH=sandbox is the valid architecture selection. This currently -only works on ia32 hosts and partly on x86-64. +works on at least IA32 hosts and x86-64 hosts. Selection of the architecture and the cross compiler can be done by using the environment variables ARCH and CROSS_COMPILE. @@ -108,13 +109,13 @@ If everything goes well, the result is a file called barebox: # ls -l barebox -rwxr-xr-x 1 rsc ptx 114073 Jun 26 22:34 barebox -Barebox usually needs an environment for storing the configuration data. +barebox usually needs an environment for storing the configuration data. You can generate an environment using the example environment contained in board/sandbox/env: # ./scripts/bareboxenv -s -p 0x10000 arch/sandbox/board/env env.bin -To get some files to play with you can generate a cramfs image: +To get some files to play with, you can generate a cramfs image: # mkcramfs somedir/ cramfs.bin The barebox image is a normal Linux executable, so it can be started @@ -133,14 +134,14 @@ given with '-i' will appear as /dev/fd[n]. If barebox finds a valid configuration sector on /dev/env0 it will load it to /env. It then executes /env/init if it exists. If you have -loaded the example environment barebox will show you a menu asking for +loaded the example environment, barebox will show you a menu asking for your settings. -If you have started barebox as root you will find a new tap device on your -host which you can configure using ifconfig. Once you configured bareboxs +If you have started barebox as root, you will find a new tap device on your +host which you can configure using ifconfig. Once you configured barebox' network settings accordingly you can do a ping or tftpboot. -If you have mapped a cramfs image try mounting it with +If you have mapped a cramfs image, try mounting it with # mkdir /cram # mount /dev/fd0 cramfs /cram @@ -157,16 +158,15 @@ Directory Layout Most of the directory layout is based upon the Linux Kernel: -arch/*/ -> contains architecture specific parts -arch/*/mach-*/ -> SoC specific code +arch/* -> contains architecture specific parts +arch/*/include -> architecture specific includes +arch/*/mach-* -> SoC specific code +arch/*/mach-*/include -> SoC specific includes drivers/serial -> drivers drivers/net drivers/... -include/asm-* -> architecture specific includes -include/asm-*/arch-* -> SoC specific includes - fs/ -> filesystem support and filesystem drivers lib/ -> generic library functions (getopt, readline and the @@ -188,7 +188,7 @@ Documentation/ -> Sphinx generated documentation. Call "make docs" to Release Strategy ---------------- -Barebox is developed with git. From time to time, tarball releases are +barebox is developed with git. On a monthly schedule, tarball releases are branched from the repository and released on the project web site. Here are the release rules: @@ -228,15 +228,15 @@ are the release rules: Contributing ------------ -For any questions regarding Barebox, send a mail to the mailing list at +For any questions regarding barebox, send a mail to the mailing list at <barebox@lists.infradead.org>. The archives for this list are available publicly at <http://lists.infradead.org/pipermail/barebox/> and <https://www.mail-archive.com/barebox@lists.infradead.org/>. -The same list should also be used to send patches. Barebox uses a similar +The same list should also be used to send patches. barebox uses a similar process as the Linux kernel, so most of the Linux guide for submitting patches <https://www.kernel.org/doc/html/latest/process/submitting-patches.html> also -applies to Barebox (except the step for selecting your recipient - we don't +applies to barebox (except the step for selecting your recipient - we don't have a MAINTAINERS file, instead all patches go to the list). @@ -246,7 +246,7 @@ License Copyright (C) 2000 - 2005 Wolfgang Denk, DENX Software Engineering, wd@denx.de. Copyright (C) 2018 Sascha Hauer, Pengutronix, and individual contributors -Barebox is free software: you can redistribute it and/or modify it under the +barebox is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2, as published by the Free Software Foundation. @@ -266,6 +266,6 @@ the above copyright and warranty notices: This eases machine processing of licensing information based on the SPDX License Identifiers that are available at http://spdx.org/licenses/. -Also note that some files in the Barebox source tree are available under +Also note that some files in the barebox source tree are available under several different GPLv2-compatible open-source licenses. This fact is noted clearly in the file headers of the respective files. |